The Intergroup Rhabdomyosarcoma Study (IRS), a collaborative effort of Children's Cancer Study Group, and Southwest Oncology Group, is a multi-disciplinary study designed to answer important questions about the treatment and biological characteristics of rhabdomyosarcoma in childhood and adolescence. Initiated in November, 1972, IRS-I closed to patient entry in November, 1978, and IRS-II began. Data otained in IRS-I bear on the surgical, radiotherapeutic, and chemotherapeutic aspects of treatment in relation to disease stage and primary site of tumor origin. Information of prognostic value relative to histology, primary site and sex emerged. Two new histologic subtypes plus patterns of disease spread in relation to primary site, of importance in design of new treatment regimens, have been identified. Two year disease-free survival rates in IRS-I are 89-90 percent in Group I, 70-75 percent in Group II, 60-65 percent in Group III and 30 percent in Group IV. Developed as an outgrowth of IRS-I, IRS-II has as its major goals to: further refine treatment in Group I; increase disease-free survival rates in Groups II-IV with prolonged intensive chemotherapy, and more aggressive radiation in Group IV: prevent CNS extension from head and neck sites with radiation and chemotherapy; assess primary chemotherapy vs primary surgery for GU tumors; develop a pathologic staging classification. As in IRS-I, IRS-II will be monitored by a multi-disciplinary steering committee composed of surgeons, radiotherapists, chemotherapists, pathologists and biometricians representing the 2 participating cooperative cancer treatment groups.